An 18-year-old boy who waded into swampy water at a reserve in Mexico was snatched by what was described as a ten-foot crocodile and is believed to have been eaten.

The youth was one of four friends who were at La Encrucijada reserve in southern Chiapas on Sunday (12 March). His three friends managed to escape and ran into town to raise the alarm.

The boys are believed to have been in a protected area and to have entered without notifying the relevant authorities, Mexico's El Universal newspaper reports. Mexico's federal environment department said it will now erect signs in the area to warn of the dangers of crocodile attacks.

The Natural Protected Areas Commission said: "The majority of these incidents are caused by people who unknowingly enter areas where fishing is not permitted." However, the commission added it was "committed to the absolute respect for human life," KPVI reported.

Officials from Mexico's National Commission of Protected Natural Areas (CONANP) said on Wednesday (15 March) that they will work with fishermen to monitor and attempt to catch any crocodiles over three metres in length. They will then empty their stomachs without harming them in an effort to find the unidentified boy's remains.

If the guilty crocodile is found, it will be taken to the Wildlife Management and Utilization Unit and then to a zoo or reserve away from humans.

In 2015 a seven-year-old boy was snatched and eaten by a crocodile in western Mexico as his father watched helplessly. Manuel Abraham was playing with a balloon which landed on a river bank. As he went to collect it, a crocodile leapt from the water and pulled him in. It was the eighth crocodile attack at the Bara Santa Ana estuary in two years.

A crocodile approaches the edge of a lagoon in the Mexican Gulf port of Tampico (file photo)REUTERS/Dave Graham